Vehicle generators powered by the engine of an automobile are used to load car batteries. A rectifier assembly of a battery charging circuit rectifies the alternating voltage output by the vehicle generator and provides a rectified battery charge voltage to the car battery. The rectifier assembly is typically based on pn diodes providing a low forward bias voltage to minimize power losses as well as a well-defined reverse breakdown characteristics to reliably protect electronic circuits in the vehicle in the case of a load dump. It is desirable to provide battery charging and generator assemblies with improved performance.